air leak sound

[jedmate]

hi taylormj4,i think the sound you are hearing when you turn off ,is probably the stepper motor plunger retracting
regards dave

[taylormj4]

jedmate said:

hi taylormj4,i think the sound you are hearing when you turn off ,is probably the stepper motor plunger retracting
regards dave

Hi Jedmate,
You nearly caught me out there opening a new thread lol !

Thanks for the suggestion but it's definitely not the stepper motor winding in. I know what that sounds like, that's more of a buzzing sound. The sound I am trying to describe is more of an air rushing noise, like an asthmatic breathing out or someone getting winded ha ha. I'd record it and stick it on here if that were possible.

[jamienshelly]

Hi
Does the noise sound like the noise you get when you have a plug out, like a compression noise, as i get this very occasionally. I have just put it down to the rush of air as an inlet/exhaust valve is just opening when the engine comes to a stop
Hope this helps
Jamie

[ChimpofDarkness]

Turn the key off & you're cutting the ignition.

But the engine is still rotating under inertia.

So the valves are still opening & closing.

The momentary chuffing, hissing or induction noise you are hearing as the engine stops rotating is what you can't hear when combustion takes place.

Remember, your engine is just an air pump, so with the ignition off & no combustion it's no surprise it sounds like an old piston compressor slowing down.

However, a hissing sound while the engine is running, a raised idle speed you can't resolve with the idle screw or by disabling the stepper motor, or white spark plug electrodes are all symptoms of an induction leak & should be investigated.

If you do suspect an induction leak while running you should invest in a can of EasySatart.

Spray a very small amount of your EasyStart in the areas you suspect may be the source of your induction leak, pause, wait 3 seconds or less & listen carefully for an increase in idle speed.

If you get a sudden increase in idle speed, you have found your induction leak.

Repeat systematically allowing time between testing each suspected area.

Please be extremely careful when using EasyStart, it is basically a highly combustible hydrocarbon.

Before you attempt the EasyStart induction leak test I strongly recommend running your engine in the dark, carefully complete a visual inspection of the HT leads & plug extenders.

You are looking for arching (sparks!), and to be very honest it's not that uncommon.

If you see any sparks at night they'll be there by day too, its just the first you'll know about it is when you find your holding a rather effective flame thrower.

Change your leaky HT leads/extenders & you should be safe to do the EasyStart induction test, just adopt caution in the area of the alternator please.

Good luck & let us all know how you get on, Dave.